Hitherto, for the sea transport of fresh foods, frozen foods, medicines that require refrigerated transport, works of art, and the like, a reefer container provided with a cooling unit in the container has been widely used. The cooling unit of the reefer container is generally driven by being supplied with power from an external power source installed in a container terminal or a container ship. In addition, in the conventional art, the cooling unit is supplied with power by connecting the external power source to the cooling unit with a power cable (for example, Japanese Unexamined Patent Application, First Publication No. H6-82155 and Japanese Unexamined Patent Application, First Publication No. 2011-37573).
In a refrigeration container described in Japanese Unexamined Patent Application, First Publication No. H6-82155 and Japanese Unexamined Patent Application, First Publication No. 2011-37573, a power plug is disposed in a refrigeration unit, and external power is supplied to the refrigeration unit by connecting a power cable from a power source box installed in a container terminal or a container ship or a power supply apparatus such as a container stand, to the power plug.